Tom Kilburn was born at Earlseaton, near Dewsbury in 1921. He attended the local Wheelwright Grammar School and then Sidney Sussex College, Cambridge, where he completed his degree in mathematics in two years according to wartime regulations. In 1942, Kilburn joined the Telecommunication Research Establishment at Malvern, where he worked on radar with Frederic Williams.
In 1946 Williams was appointed professor of electro-technics [electrical engineering] at the University of Manchester, and Kilburn joined him as research assistant (he also registered for a Ph.D. which he received in 1948). One of Williams' research interests was the use of cathode ray tubes (CRT) to store information for use in digital computers. The tubes stored information in the form of a charge distribution on the back of the screen, and one of the key challenges was to ensure this did not degenerate. To work for a digital computer, a means was required which allowed many information bits to be held in the CRT in such a way that each bit could be written or read at high speed and would keep its value indefinitely between rewrites. By late 1947, Williams and Kilburn had demonstrated that CRT storage was workable, and Kilburn then developed a basic computer to test this CRT memory storage. In December 1947 Kilburn completed a progress report for the TRE, "A storage system for use with binary digital computing machines". In this he presented a definitive explanation of how CRT could be used as an electronic storage device.
The Manchester computer, known as the Small Scale Experimental Machine (SSEM) or more popularly the Baby', was able on 21 June 1948 to run the first stored digital computer program. This was a major breakthrough, and Kilburn worked on developing the functionality of this machine. An enhanced version of SSEM known as the Manchester Mark I was operational by early 1949 and this was further developed by Ferranti Ltd, into the first commercial computer - the Ferranti Mark 1. In the process, a number of inventions were incorporated, including the introduction of index (or address modification) registers, and a two-level store based on a number of CRTs and a magnetic drum store. Kilburn and his colleagues took out a number of patents for these inventions, and these were later to prove a useful source of income to the University.
With the Mark I operational, Williams spent less time on computers, and it was left to Kilburn to lead on this aspect of the Department of Electrical Engineering's work. Kilburn's research team developed other computers including the MEG or Mark II Computer (MEG was a shortening of megacycle engine), which used locating point hardware to conduct mathematical calculations (a commercial variant of MEG called Mercury was developed by Ferranti). A Mercury computer was used by the University between 1957 and 1963.The other machine, known as the Transistor Machine, was an experiment in the use of transistors for computer design, and was probably the world's first transistor computer. Kilburn's own interest was in processor architecture rather than the applications of computing. His approach was to develop working machines and analyse and improve their operations, rather than focus on the theoretical background of computing machinery.
By the late 1950s there was growing concern about the lack of fast computers in the UK. In response, Kilburn developed the Muse project (the word is derived from microsecond) to build a computer with much greater immediate access storage capacity. The project attracted interest from industry and research bodies, but was extremely ambitious in scope and funding was uncertain. The department developed a more basic version based on work by Dai Edwards and Tony Brooker. In 1958, Ferranti became involved with the project, and support was also provided by the National Research Development Corporation. This collaboration eventually resulted in the ATLAS computer, an ambitious project that pioneered many concepts in storage and addressing which are in common use today. It had a one level memory system, which was an early stage in the development of virtual memory. Atlas was also innovative in its use of multiprogramming. On its official inauguration on 7 December 1962 it was considered to be the most powerful computer in the world.
The Department's last major 'big' computer project was the MU5. Planning for this began in 1966 and it was intended to be 20 times faster than Atlas. MU5 aimed to run high level language programs more efficiently. The project received funding from the SRC and ICL assisted with production facilities (mainly at its West Gorton plant). The MU5 design team included Kilburn, Dai Edwards, Frank Sumner, D Aspinall and J S Rohl.
Kilburn was a lecturer at the University of Manchester from 1948 (he had been on secondment from the TRE between 1946 and the end of 1948, when he resigned from the civil service). He was promoted to senior lecturer in 1951 and reader in electronics in 1955. In 1960 Kiburn was made professor of computer engineering (the title changed to computer science in 1964). Kilburn oversaw the development of the new Department of Computer Science in 1964, which introduced undergraduate degrees in computer science. This was the first computer science department in the UK. Kilburn was dean of the faculty of science from 1970 to 1972, and as pro-vice-chancellor from 1976 to 1979. Kilburn retired in September 1981, and was made an emeritus professor.
Professor Kilburn received honorary degrees from Essex, Brunel, Bath, CNAA and Manchester, and honorary fellowship from UMIST. He was appointed FRS in 1965, received the Society's Royal Medal in 1978, and served on its Council in 1978-9. He also received numerous awards from electrical engineering and computing bodies. Tom Kilburn was appointed CBE in 1973.
Kilburn married Irene Marsden (1921-1981), who was also from Dewsbury, in 1943, and they had two children, John and Anne.
